We all claim what we do is the mesorah.
The gemarah says is sanhedrin the the talmidim all said their rebbe is THE moshiach (of all jews)
So clearly this is not a new thing, (maybe by the litvaks is wasn’t done for many generations, so the question is on them not us, and by chassidim it was done for many generations, in ruzin, tzenabel, chabad etc)
And litvaks do the same thing too. Rav chaim was THE gadol hador, or Rav shach etc.
There are many things that litvaks do that i think is not mesorah, like skipping chazaras hashatz in yeshiva. The way they learn “lumdos” before learning kol hatorah kulah biderech kitzara as it says in sh”u. Women going to work, whereas the posuk says kol kvoda bas melech penima, and many other things – davening so fast